315797821 has 2 divisors, whose sum is σ = 315797822. Its totient is φ = 315797820.

The previous prime is 315797813. The next prime is 315797857. The reversal of 315797821 is 128797513.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 173949721 + 141848100 = 13189^2 + 11910^2 .

It is a cyclic number.

It is not a de Polignac number, because 315797821 - 2³ = 315797813 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (315797861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 157898910 + 157898911.

It is an arithmetic number, because the mean of its divisors is an integer number (157898911).

Almost surely, 2^315797821 is an apocalyptic number.

It is an amenable number.

315797821 is a deficient number, since it is larger than the sum of its proper divisors (1).

315797821 is an equidigital number, since it uses as much as digits as its factorization.

315797821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 105840, while the sum is 43.

The square root of 315797821 is about 17770.7011960699. The cubic root of 315797821 is about 680.9831662006.

The spelling of 315797821 in words is "three hundred fifteen million, seven hundred ninety-seven thousand, eight hundred twenty-one".